Historical Q: Darwin and Kelvin

Allan Harvey (aharvey@boulder.nist.gov)
Fri, 12 Nov 1999 12:23:11 -0700

A query for the history-minded out there ...

I've just finished a book a friend gave me called "Scientific Blunders"
(subtitle "A Brief History of How Wrong Scientists Can Sometimes Be") by
Robert Youngson (Robinson Publishing, London, 1998). It is not an
anti-science book; it tries to show how good science works by
telling stories of blunders made by bad science and also times when good
science has gone in wrong directions. So its agenda is reasonable.

Unfortunately, the book seems riddled with errors -- when the writing was
about things I knew about the writer got a lot of things just plain wrong
(from minor things like placing Dartmouth in Massachusetts to major things
like grossly misstating the doctrine of Original Sin and goofing up basic
facts of the Manhattan Project). One area in which I suspect Youngson goofed
up is relevant to this listserv, concerning the effect of William Thomson's
(later Lord Kelvin) calculations of the age of the Earth to the acceptance
(or lack therof) of Darwin's theories.

Youngson says (p. 29):
"Darwin was shocked, because Thomson's figure for the age of the earth
eliminated the possibility that his theory of evolution could be correct.
There simply would not have been time for the geological processes on which
Darwin's theory was based to have occurred. If Thomson was right, the earth
must have been created with a ready-made geology. Archbishop Ussher's date
of 4004 BC could be right."
He then tells of Darwin's son George verifying Thomson's calculations, and
then tells how those calculations were underestimates because of incorrect
assumptions about how the Sun worked and because he was not aware that heat
was generated in the Earth via radioactivity. The overall picture he paints
is one in which Kelvin had scored what even Darwin perceived as a near
knockout blow against evolution, and that the theory was only saved by the
discovery of radioactivity.

Is this characterization anywhere near the truth? Kelvin's age calculations
gave about 100 Myr, a factor of 45 less than the current best number. But
was enough known about the "speed" of evolution in the late 19th century to
say that 100 Myr would not have been enough time for Darwin's postulated
evolution to have happened? Certainly the more time the better for Darwin,
and if Kelvin had come up with 100,000 years that would have been a huge
blow to Darwinism. But was 100 Myr really low enough to discourage Darwin
and temporarily turn scientific opinion against evolution? Or has Youngson
gotten things wrong here as well?

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| Dr. Allan H. Harvey | aharvey@boulder.nist.gov |
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